EyeQue Personal Vision Tracker Bundle - Smartphone Vision Tests - Screening & Track Changes

What are the differences between the different EyeQue devices and bundles? There’s several that look pretty similar but are called different things.

Will this check the prescription that your existing glasses (lenses) actually have?

What is the difference between all the devices? They look like they all do the same thing?

Is it returnable if I can’t get it to work successfully?